linux-kernel - Re: [PATCH] char: misc: Use IS_ERR() for filp

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Message-ID: <aU9BgOhtDdahBCKo@quatroqueijos.cascardo.eti.br>
Date: Fri, 26 Dec 2025 23:16:32 -0300
From: Thadeu Lima de Souza Cascardo <cascardo@...lia.com>
To: Alper Ak <alperyasinak1@...il.com>
Cc: arnd@...db.de, gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	kernel test robot <lkp@...el.com>,
	Dan Carpenter <dan.carpenter@...aro.org>
Subject: Re: [PATCH] char: misc: Use IS_ERR() for filp_open() return value

On Sat, Dec 27, 2025 at 02:02:48AM +0300, Alper Ak wrote:
> filp_open() never returns NULL, it returns either a valid pointer or an
> error pointer. Using IS_ERR_OR_NULL() is unnecessary. Additionally, if
> filp were NULL, PTR_ERR(NULL) would return 0, leading to a misleading
> error message.
> 
> Fixes: 74d8361be344 ("char: misc: add test cases")
> Reported-by: kernel test robot <lkp@...el.com>
> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> Closes: https://lore.kernel.org/r/202506132058.thWZHlrb-lkp@intel.com/
> Signed-off-by: Alper Ak <alperyasinak1@...il.com>
> ---
>  drivers/char/misc_minor_kunit.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/char/misc_minor_kunit.c b/drivers/char/misc_minor_kunit.c
> index 6fc8b05169c5..e930c78e1ef9 100644
> --- a/drivers/char/misc_minor_kunit.c
> +++ b/drivers/char/misc_minor_kunit.c
> @@ -166,7 +166,7 @@ static void __init miscdev_test_can_open(struct kunit *test, struct miscdevice *
>  		KUNIT_FAIL(test, "failed to create node\n");
>  
>  	filp = filp_open(devname, O_RDONLY, 0);
> -	if (IS_ERR_OR_NULL(filp))
> +	if (IS_ERR(filp))
>  		KUNIT_FAIL(test, "failed to open misc device: %ld\n", PTR_ERR(filp));
>  	else
>  		fput(filp);
> -- 
> 2.43.0
> 

Acked-by: Thadeu Lima de Souza Cascardo <cascardo@...lia.com>